Search results

  1. 1

    50hp Mercury 500 lower unit swap

    I have a 1974 50hp Mercury 500 ser#4073302. My lower unit is locked up I have found one but it is listed as being from an early seventies red stripe 50hp with 11 splines on the drive shaft mine has 13 splines. I thought the redstripes were merc 500s also. If anyone could shed some light I...
  2. 1

    1974 Mercury 500 Thunderbolt lower unit swap

    Re: 1974 Mercury 500 Thunderbolt lower unit swap Thanks again for all the help. Well, I checked and everything matches up: drive shaft length, number of splines on drive shaft, shift shaft, and prop shaft. In the new pics it shows mine with the cam base (i removed the cam and made a not of...
  3. 1

    1974 Mercury 500 Thunderbolt lower unit swap

    Re: 1974 Mercury 500 Thunderbolt lower unit swap I have done some homework and think I can accomplish this. The issue I have come up with but can't find any info on is that it seems there is an insert in the cavity that the shift rod goes into. The insert makes the slot round whereas the...
  4. 1

    1974 Mercury 500 Thunderbolt lower unit swap

    I have a 1974 I believe 50hp Mercury 500 Thunderbolt Serial #4073302. The Lower unit I want to use is from a 50s model 50hp mercury. Everything looks the same except for the replacement doesn't seem to have the Reverse shift cam or base on the shift rod just the bushing that has the slot thru...
Top